“He’ll tell me what to do, and if it’s illegal, guess what’s going to happen? I’m gonna say, ‘Mr. President, that’s illegal,’” Gen. John Hyten told the Halifax International Security Forum. Hyten, commander of U.S. Strategic Command, declared he would not follow an “illegal” order to launch nuclear weapons.

The context for the general’s comment was, of course, North Korea. President Donald Trump in August famously promised “fire and fury,” and in September he threatened to “totally destroy” the North. These explosive words were on top of many pledges not to allow Pyongyang to develop weapons that could threaten the American homeland.

No wonder many have been concerned that Trump, by ordering a first nuclear strike on North Korea, will violate international law and norms and blow up the planet. He just might manage to do that—who knows?—but you don’t have to worry he will violate norms or law.

As an initial matter, Gen. Hyten was on firm ground when he said he would refuse to obey an illegal order from the commander in chief. David Maxwell of Georgetown University points out that enlisted personnel in the American military take an oath to follow the orders of the president but officers do not. Officers swear or affirm to “support and defend the Constitution.”

“The difference in the two oaths is important, and it is what makes our officer corps different from those in so many other countries,” Maxwell, a retired U.S. Army colonel who served five tours of duty in South Korea, told The Daily Beast in response to a question about Hyten’s provocative comment. “We seek to defend the idea and ideals of our nation and our political philosophy and are loyal to those ideas and ideals and not to an individual who holds office.”